Why does outliner show a different object selected
As far as I know it was intended, where in Maya it always sync, but I know there is a good reason to make it unsync, I've read about it like sometimes ago but forgot what it is, but make it unsync can be confusing sometimes. 
So there is a Gsoc branch for outliner which has an options to make it sync or unsync mode between outliner and viewport, it is not in the master just yet, but let's hope it will eventually at the end.
See the discussion here :

https://devtalk.blender.org/t/gsoc-2019-outliner-weekly-reports/7642/7

https://devtalk.blender.org/t/gsoc-2019-outliner-branch-testing/7616/63